Novel synthesis of silica-coated ferrite nanoparticles prepared using water-in-oil microemulsion

Teruoki Tago, Takatoshi Hatsuta, Kanta Miyajima, Masahiro Kishida, Shizuka Tashiro, Katsuhiko Wakabayashi

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146 Citations (Scopus)


Ferrite nanoparticles (magnetite (Fe3O4) and cobalt-ferrite (CoxFe3-xO4)) coated with silica (SiO2) were prepared using water-in-oil microemulsion of a polyoxyethylen(15)cetylether/cyclohexene system. Observation via transmission electron microscopy revealed that the ferrite nanoparticles were located nearly at the center of spherical SiO2 particles. The sizes of Fe3O4 and CoxFe3-xO4 nanoparticles were in the range of 8-12 nm and 10-14 nm, respectively, and the thickness of the SiO2 layer was ∼ 14.0 nm. The solid solution of cobalt ions into Fe3O4 to form CoxFe3-xO4 nanoparticles led to an increase in the coercivity of the SiO2-coated ferrite nanoparticles. The coercivity increased with increasing amounts of added cobalt, obtaining a maximum value of 780 Oe around a Co/Fe ratio of 0.3-0.4.

Original languageEnglish
Pages (from-to)2188-2194
Number of pages7
JournalJournal of the American Ceramic Society
Issue number9
Publication statusPublished - Sept 2002

All Science Journal Classification (ASJC) codes

  • Ceramics and Composites
  • Materials Chemistry


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